Empid ID Challenge

Empidonax flycatchers… you can’t live with them, you can’t build a complete life list without them. As countless as the stars above have been the brillant birders brought low by these humble homunculi, these tiny little iterations on an undistinguished theme. Such has become the fate of our friend Alberto Lopez, late of Puerto Rico but recently relocated to Ithaca, NY (just in time for fall too!) Alberto is an ace photographer; many of his images helped support our May 2009 Puerto Rico Month series, notably his shots of the stealthy Puerto Rican Screech-owl. You can see some of his superb images at his old blog or eagerly await his new one. To tide you over, he’s offered us one excellent image along with a plea for help:

I just moved from Puerto Rico to Ithaca… and as you might guess I am going mad birding every chance I get. Lots of new species for me, trying to learn their calls and fieldmarks wow! I feel like I’m starting all over again, I was already use to going birding without a field guide but now its a must! And ive been able to id almost everything but this little flycatcher. This photo was taken in Sapsucker Woods.

Alberto has his own thoughts about what species this bird is but alas cannot flesh out the sighting with any information about the bird’s vocalization or behavior. Do you dare try to identify this empid based on timing, geography, and the photo below? I invite any and all insights in our comments section but be warned: I have no freaking idea what flycatcher this is!

Mike is a leading authority in the field of standardized test preparation, but he's also a traveler who fully expects to see every bird in the world. Besides founding 10,000 Birds, Mike has also created a number of other entertaining but now extirpated nature blog resources, particularly the Nature Blog Network and I and the Bird.

My first impression was that it is a Empidonax because of its size, it seemed relatively small, I also had a brief chance to see a Contopus Flycatcher that same day and it had a darker coloration and was larger. I am stumped!

This is probably lucky for me that I just posted this species (assumably) on my blog a few days ago. Lack of eye-ring/post-ocular spot and completely yellow lower mandible puts this in the “Traills” complex. Dusky, Hammond’s, and Gray have smaller structures and elongated, daintier bodies. Cordilleran/Pac-Slope have yellow lower mandibles but have eye-rings as well. Least has an eye-ring and post-ocular teardrop. Structure also eliminates other birds like Acadian. Contrasting throat to head also is good for “Traill’s.” Wings look short and tail looks long, so I believe this is a Willow Flycatcher. Overall brown tones and large head help as well. From my experience, I would say Alder is more contrasting in the throat area than this bird. Boy, I hope I’m right!

This looks like a Willow/Adler. The eyering is quite weak, and the primary projection (length of the primaries past the end of the tertials on the folded wing) is moderate. We can easily eliminate Least & Yellow-bellied Flycatchers, which both have strong eyerings. Acadian has a longer bill and is more greenish on the back. Willow and Alder are best told apart by voice and can be difficult or impossible to separate in the hand. A beautiful photo – wish I’d taken it.